Vertical Cavity Surface Emitting Laser (VCSEL) arrays are often used in fiber optic communications. These VCSEL arrays are capable of transmitting large amounts of data over small optical fibers. A single ⅛ inch fiber bundle may carry an entire 12–20 bit logical port running at relatively high speeds. VCSEL arrays are constructed using semiconductor process techniques similar to those used in silicon integrated circuits, however, the process techniques used for VCSEL arrays may not be optimal for construction of high speed silicon integrated circuits. This makes it difficult to integrate VCSEL arrays and high speed circuits on the same silicon device.
Many current uses of VCSEL technology require precise performance specifications in order to transmit signals over long distances via optical fibers. However, in situations where only short distances are required, such as within a computer server or within a single data center, less stringent performance specifications are required of the VCSEL arrays.
Currently, some circuit boards include VCSEL array modules and receiver modules for communication between computers. Typically, these modules are placed along one edge of the board and electrically connected to one or more electronic devices attached to the board. These solutions work well, however as computer speeds continue to increase, the delay inherent in driving signals out of an electronic device, into a board, along a board electrical connector, and into a VCSEL array module becomes increasingly troublesome to engineers designing high-speed computers.
Further, board space may be very expensive and in short supply especially in devices such as desktop systems or blade servers. The footprint of separate VCSEL array modules and, if needed, their translator/terminator devices may become a substantial portion of total board area, thus increasing size and costs of the computer.